1. Field of the Invention
The present invention relates to pest control agents for controlling pests such as honeybee parasitic pests, and a pest control method using the pest control agents.
2. Related Background Art
Not only are honeybees used for collecting honey, but also the use ratio as beneficial pollinator insects is now increasing. It has been reported that the annual economic value of honeybee pollination has reached 5 to 10 billion dollars in the United States and is expected to be 100 or more times the economic value of honeybee products including honey. The number of colonies of bees kept at present is 9 million in China, 9 million in the regions of the former Soviet Union, 3 million in the United States, 3 million in Mexico, 2 million in Brazil, 1.50 million in Argentina, and 0.20 million in Japan. Thus, the beekeeping industry is one of important sectors of agriculture in any countries in the world.
Recently, Colony Collapse Disorder (CCD) has become problem worldwide, and serious influences on the beekeeping industry due to the decrease in the number of honeybee colonies have been reported. It is said that Colony Collapse Disorder is attributable to adverse influences on honeybees from honeybee parasitic pests including Varroa destructor (Kagaku to Seibutsu (Bioscience & Biotechnology), 2010, vol. 48, no. 8, pp. 577 to 582 (NPL 1)), neonicotinoid-based chemicals, or the like.
At present, amitraz, fluvalinate, coumaphos, formic acid, sucrose octanoate ester, organic acids such as β-acid, and the like are known as chemicals for Varroa destructor control. In addition, chemicals under studies include a triazine-based insecticide cyromazine (International Publication No. WO2012/156342 (PTL 1)), a hydrazine-based insecticide bifenazate (International Publication No. WO2012/156344 (PTL 2)), and the like. However, the number of chemicals highly safe to honeybees is still small, and there are problems of parasitic pests resistant to insecticides. Hence, a chemical for honeybee parasitic pest control having a novel action and high safety is strongly desired.
In such circumstances, a novel chemical for honeybee parasitic pest control has been further searched for. A compound of the present invention includes a compound described as a pest control agent in Japanese Patent No. 4993641 (PTL 3) and International Publication No. WO2013/129692 (PTL 4). However, the literatures do not state at all that the pest control agent has an effect against honeybee parasitic pests. Moreover, European Patent Application Laid-Open No. 432600 (PTL 5) discloses a compound having a structure similar to the compound of the present invention, but fails to provide any description or suggestion regarding safety to honeybees and effect against honeybee parasitic pests.
Further, Japanese Unexamined Patent Application Publication No. Hei 5-78323 (PTL 6) and European Patent Application Laid-Open No. 268915 (PTL 7) disclose a structural formula of N-[1-((6-chloropyridin-3-yl)methyl)pyridine-2(1H)-ylidene]-2,2,2-trifluoroacetamide, but fail to provide any description or suggestion regarding safety to honeybees and effect against honeybee parasitic pests.
Chemische Berichte (1955), 88, 1103-8 (NPL 2) discloses a plurality of compounds having a ring structure similar to the compound of the present invention, but the compounds are disclosed only as synthetic intermediates.
European Patent Application Laid-Open No. 259738 (PTL 8) discloses a plurality of compounds having a ring structure similar to the compound of the present invention, but fails to disclose or suggest a compound having a trifluoroacetic acid imino structure.